The easiest way to define an alert is by using the Alert Wizard, which can be invoked from the Tools menu. Alerts may also be created and maintained in the Alerts dialog, which can be opened from the Tools menu. Alerts are stored as part of the QlikView document. Alerts can only be created and triggered from Windows versions of QlikView (that is, not from AJAX clients).
QlikView alert checks can be triggered in three different ways:
- Automatically in the QlikView layout when there is a probability that the document’s data has changed, i.e. when the document is opened, when the script has been executed or when a Reduce Data operation has been performed.
- Manually from a macro via special Automation APIs. Refer to the QlikView API guide for details.
- External programs running QlikView in batch mode have a special Automation API to retrieve a list of fired alerts from a given context.
The chain of events following the triggering of an alert check can be shown as follows:
Alerts can be suspended after being fired until a change occurs. As an example it may be quite annoying to be reminded every time you open a document that your budget goal has been fulfilled. In that case you may set the alert to fire only once and then suspend itself until next month.
As can be seen in the flowchart, each triggering of an alert initiates a chain of logical operations in the QlikView document. Typically QlikView has to perform the following major steps:
- Applying the selection relevant to the alert.
- Calculating the condition expression value.
- Restoring original selections.
The time needed to perform action 1 and 3 is of course each equal to the normal “click times“ if the selections had been applied interactively. The time needed for step 2 is the same as if the expression had resided e.g. in a sheet object. Added together, the time needed to check an alert can be quite substantial in large documents. This may be of less importance for single alerts triggered on opening or reload, but caution should be exercised when using large amounts of macro-triggered alerts, so that the document does not become sluggish.
Opens the Alerts dialog where all QlikView alerts are created and maintained.